1. Technical Field
The present invention relates generally to a method of providing proximity service communication between terminals supporting multi-radio access technology and, more particularly, to a method of providing proximity service communication between terminals by performing direct communication between terminals or locally routed communication via an identical base station.
2. Description of the Related Art
In 3rd Generation Partnership Project (3GPP) Service and System Aspects (SA), communication based on proximity between terminals is provided under the name of “Proximity Service (ProSe).” For this, communication between terminals is provided either using no network infrastructure for data transmission or using a minimum network infrastructure such as only a base station. Network infrastructure in this patent means network entities providing communication services for terminals and managing communication networks.
ProSe is intended to support commercial services, social networking, network offloading, etc. ProSe includes direct communication between terminals (direct mode) and locally routed communication via an identical base station (locally routed mode).
In addition to the ProSe of 3GPP, technologies and standards related to direct communication between terminals include FlashLinQ of Qualcomm, Wi-Fi Direct of WiFi Alliance, IEEE 802.15.8 Peer Aware Communication (PAC) of IEEE, etc.
FlashLinQ, which is technology for direct communication between terminals in a licensed band, is capable of providing communication between terminals within the range of 1 mile (1.6 km), and has the field of applications, such as in social networking and advertising services.
IEEE 802.15.8 PAC is under standardization to provide social networking, advertising, games, etc. between users within the range of 1 km.
Wi-Fi Direct is direct communication using an unlicensed band between terminals, each having a wireless local area network (Wi-Fi or WLAN) interface.
In addition, as a standard related to proximity service communication, IEEE 802.11aq Pre-Association Discovery (PAD) is under standardization.
IEEE 802.11aq PAD is intended to standardize communication between a WLAN terminal and a counterpart WLAN access point before the WLAN terminal is associated with the WLAN access point.
Since network infrastructures used in IEEE 802.11aq are only access network resources such as WLAN access points and servers connected to the WLAN access points (for example, a printer server, a web server, a file server, etc.), IEEE 802.11aq may be considered as proximity service communication in a broad sense.
Research into proximity service communication is currently being conducted based on schemes for searching for proximity service communication-supporting terminals and searching for proximity-based services, on the basis of single radio access technology, but research into proximity service communication in heterogeneous networks for providing multi-Radio Access Technology (RAT) has yet been sufficiently conducted.
If proximity service communication is assisted by heterogeneous networks, proximity service communication can reduce load of wireless/wired networks and provide various communication services.
Meanwhile, a traffic load distribution scheme based on a conventional network infrastructure has limitations. That is, a traffic load can be distributed to other networks only when a network infrastructure, such as a base station, is present. Even if two terminals use the same base station, they communicate with each other through a core network, and thus a burden on the core network is increased.
Further, research into switching between the use of proximity service communication and the use of a network infrastructure is not sufficient.
If a distance between terminals is increased, or if it is difficult to perform proximity service communication due to hindrance such as radio interference, the network infrastructure must be used again, but methods of switching to the use of the network infrastructure without releasing a connection between the terminals have not yet been desirably described.
For example, when two terminals, which are performing proximity service communication via Wi-Fi Direct, become far away from each other due to the movement thereof, the use of a Long Term Evolution (LTE) infrastructure is required again. In this case, a delay time required to switch to the use of the LTE infrastructure must be minimized.
Further, it is difficult to select suitable radio access technology necessary for communication with a neighboring terminal.
For proximity service communication, terminals must use the same radio access technology, but it is difficult to know which radio access technology can be used by the two terminals without network assistance. For example, when terminal 1 can use FlashLinQ and ProSe, and terminal 2 can use ProSe and Wi-Fi Direct, it is difficult for the two terminals to simultaneously select ProSe without the aid of a network infrastructure.
Meanwhile, it is also difficult to search for a terminal or a server for proximity service communication. Also, it is difficult to search for a terminal or a server providing communication services desired by a user via proximity service communication. For example, in order to search for a terminal that provides proximity service communication without the aid of a network infrastructure, significant time may be required.
As another example, when a user desires to receive specific video content via proximity service communication, it may be difficult to search for a terminal containing the video content using only proximity service communication without the aid of a network infrastructure.
Further, it is difficult to search for a service meeting a user's requirement using only proximity service communication. At the present time, although schemes for providing local information for proximity service communication have been presented, such local information is randomly transferred in general to users regardless of whether the users need the local information. For example, if information about business wear shoes is received via proximity service communication although a user desires information about sport shoes, the user may feel inconvenienced due to unnecessary advertisements.